Carriage for eddy current probe having contact ball engagement between carriage and translation means

Abstract

An eddy current probe for detecting material flaws by inducing and measuring eddy currents in the surface of a material. The probe is held at a constant lift-off distance from the surface by a probe carriage that slides across the surface in a straight scan line. The carriage moves relative to a motorized bracket that slides the carriage across the surface. This relative movement allows the carriage to move across an uneven surface without deflecting the probe from a straight scan line. The probe has a split core so that an adjacent pair of coils project and detect electromagnetic fields on the surface being measured. Both coils have opposing flat sides that allow the coils to be closely packed together within the probe body.

What is claimed is: 
     
       1. An apparatus for monitoring eddy currents comprising: an eddy current probe having at least one current carrying coil;   a carriage body on which said probe is mounted and in slidable contact with a surface of a stationary cylindrical body such that said probe is held a constant distance from said surface;   a translation means for moving said carriage body and eddy current probe along a scan line across said surface, said scan line being parallel to the axis of said cylindrical body, and   coupling means for coupling said carriage to said translation means for moving said carriage and said probe along a predetermined probe path parallel to said axis, wherein said coupling means allows relative movement between said carriage and translation means such that said probe does not veer from said predetermined scan line, said coupling means comprising a carriage plate fixed to said translation means, and slidably and pivotably contacting said carriage body,   wherein said carriage plate having relative movement with respect to said carriage body and said carriage plate includes bracketing side panels having slots or post slidably engaging posts or slots on at least two sides of said carriage body.   
     
     
       2. An apparatus for monitoring eddy currents comprising: an eddy current probe having at least one current carrying coil;   a carriage body on which said probe is mounted and in slidable contact with a surface of a stationary cylindrical body such that said probe is held a constant distance from said surface;   a translation means for moving said carriage body and eddy current probe in a scan line direction parallel to the axis of said cylindrical body, and   coupling means for coupling said carriage to said translation means for moving said carriage and said probe along a predetermined probe path parallel to said axis, wherein said coupling means allows relative movement between said carriage and translation means such that said probe does not veer from said predetermined scan line path, said coupling means comprising a carriage plate fixed to said translation means, and slidably and privotably contacting said carriage body;   said carriage plate having relative movement with respect to said carriage body and said carriage plate includes bracketing side panels having slots or posts slidably engaging posts or slots on at least two sides of said carriage body, said carriage plate is coupled to said carriage body via a contact ball attached to said carriage plate, said contact ball being in slidable and pivotable engagement with a hole in said carriage body, wherein a shaft bracket attached to the carriage body confines said contact ball within said hole.   
     
     
       3. An apparatus comprising: an eddy current probe having an inductance coil oriented with an axis substantially perpendicular to an interior surface of a hollow metallic cylinder;   an eddy current probe bracket holding said probe;   a carriage body attached to said probe bracket and probe, comprising feet slidably engaging said surface and supporting said probe a constant distance above said surface;   a carriage plate having a slot or post slidably engaging a post or slot on said carriage body to provide relative movement between said body and plate in a direction parallel to said axis of the coil, and to provide limited rotational movement between said body and plate about an axis orthogonal to said axis of the coil;   a mount bracket fixed to said carriage plate comprising translation means for moving along a straight scan line path parallel to the axis of said cylinder, and   a contact ball attached to said carriage plate and slidably engaging said carriage body such that said carriage body and probe move in a straight path parallel to said straight path of said mount bracket.   
     
     
       4. An apparatus as in claim 3 further comprising a spring between said carriage plate and said carriage body, said spring exerting a biasing force against said body and towards said surface. 
     
     
       5. An apparatus as in claim 3 further comprising pivot balls between said carriage plate and carriage body.